Protein Family Models

This family constitutes holin proteins from the dsDNA Siphidoviridae group bacteriophages with two transmembrane segments. Most bacteriophages require an endolysin and a holin for host lysis. During late gene expression, holins accumulate and oligomerise in the host cell membrane. They then suddenly trigger to permeablise the membrane, which causes lysis by allowing endolysin to attach the peptidoglycan. There are thought to be at least 35 different families of holin genes [1]. [1]. 11459934. Holins kill without warning. Grundling A, Manson MD, Young R;. Proc Natl Acad Sci U S A 2001;98:9348-9352. [2]. 17012400. Abortive phage resistance mechanism AbiZ speeds the lysis clock to cause premature lysis of phage-infected Lactococcus lactis. Durmaz E, Klaenhammer TR;. J Bacteriol. 2007;189:1417-1425. (from Pfam)

Date:

2024-10-16

SPP1 phage holin family protein may function in the transport of murein hydrolases (endolysins) across the cytoplasmic membrane to the cell wall where these enzymes hydrolyze the cell wall polymer as a prelude to cell lysis

Date:

2020-05-29

This HMM represents one of more than 30 families of phage proteins, all lacking detectable homology with each other, known or believed to act as holins. Holins act in cell lysis by bacteriophage. Members of this family are found in phage PBSX and phage SPP1, among others.

Date:

2022-10-24